GRUB ls hangs when USB connected

[Michael Strack]

\- Machine :: HP Pavilion dv6 notebook  

\- Architecture :: 64-bit  

\- BIOS (not UEFI) :: version F.1C, firmware is Insyde H2O Rev. 3.5  

\- Problem :: GRUB2 shell hangs on ls command when USB attached  

  

Steps to produce problem:  

  

1\. Get GRUB shell by booting Super GRUB2 Rescue Disk on DVD (i386-pc  

version)  

2\. Run ls with no USB storage attached; detects internal HDD (and  

partitions) and CD/DVD-ROM drives as expected  

3\. Reboot after plugging in USB storage and run ls; hangs with  

increasing fan spin  

  

Troubleshooting attempted:  

  

\- Tried 2x different USB flash sticks, 1x USB external HDD, various  

USB ports  

\- Made bootable USB media under Windows using Rufus (for legacy  

BIOS/MBR target) and confirmed working  

\- Tried installing GRUB to USB using floppy emulation (but not quite  

sure what I was doing)  

  

Any advice, help, or pointers to documentation appreciated. From  

reading around, Pavilion models seem to have a particularly heinous  

BIOS.